CoordinatorLayout

CoordinatorLayout is meant to be like a super-powered FrameLayout with
three major additional capabilities:

* Aligning views relative to other views arbitrarily nested within
  other siblings (e.g. floating action buttons aligning to one edge of
  a content pane)

* Aligning views relative to keylines defining horizontal positioning

* Defining pluggable interaction behaviors from layout xml

This patch implements the first two features and some of the initial
plumbing for the third.

Change-Id: I9c368d298cd35ff507ce5c8449a572fbfe9e5da7
8 files changed